Basically, for endurance, the best source of energy is complex carbohydrates. Taking in carbohydrates an hour before exercising can help sustain energy, according to Ellen Coleman RD, MA, MPH. Proteins, on the other hand, aren't energizers. They help your immune system, provide your body with amino acids, and strengthen cells and tissues. But, to rely heavily on proteins over an extended period of time, risks kidney and liver damage.
Technically, if you have fat on your body, you don't need much fat in your diet for energy. That is, unless you are really exerting yourself. Matt Samuels, RD at the Sports Nutrition Connection says that if you are "performing at 70% or higher," then 40-50% of your energy is supplied by fat. So, if you plan to be boot-packing quite a bit in a day, you want to bring along some good fats to snack on. "Good fats" would be things like nuts, seeds, olive oil, and avocados.
A healthy diet does include fat, of course. But especially for athletes, a diet of mostly carbohydrates (55-65%), about 10-15% proteins, and then maybe 25-30% fat is best for stamina. So, that means that before and during your snowboarding vacation, you should stock up on pastas, whole grains (oatmeal, rice, granola, bread), starchy vegetables (potatoes, corn) legumes and some fibrous vegetables and fruit (vitamins) for best results.